Control circuit for automatically shutting off the windshield wipers subsequent to washer operation

ABSTRACT

In a preferred form, this disclosure relates to an electrical control system having a control circuit means for initiating conjoint operation of a windshield wiper unit and washer unit for an automotive vehicle in response to momentary depression of a washer button switch and for automatically shutting off the wiper unit subsequent to the cessation of washer operation. The electrical control system comprises a power source, an electric motor means, an electrically operated washer unit and a first control circuit means including a manual switch for effecting either low or high speed continuous operation of the wipers and a second control circuit means including a manually operated washer switch for controlling operation of the washer unit and for initiating conjoint operation of the wiper unit with the wiper unit shutting off automatically subsequent to the cessation of washer operation.

United States Patent Sheldrake 1 Sept. 12, 1972 [54] CONTROL CIRCUIT FOR3,609,496 9/1971 Peroy ct al ..318/444 AUTOMATICALLY SHUTTING OFFTHEWINDSHIELD WIPERS Primary Examiner-Benjamin Dobeck SUBSEQUENT oWASHER AttorneyW. E. Finken et al.

[72] OPERATION 57] ABSTRACT Inventor: Leonard J. Sheldrake, Noblesville,Ind.

[73] Assignee: General Motors Corporation,

Detroit, Mich. I

[22] Filed: Aug. 25, 1971 [21] Appl. No.: 174,603

[52] US. Cl. ..318/443, 318/D1G. 2, l5/250.13

[51] Int. Cl. ..H02p 3/16 [58] Field of Search ..3 l 8/DIG. 2, 443, 444;l5/250.l3

[56] References Cited 7 UNITED STATES PATENTS 3,032,270 5/1962 Corbin..318/443 X 3 ,25 3,206 5/1966 Romanowski ..318/466 3,500,159 3/1970Keams ..318/443 X In a preferred form, this disclosure relates to anelectrical control system having a control circuit means for initiatingconjoint operation of a windshield wiper unit and washer .unit for anautomotive vehicle in response to momentary depression of a washerbutton switch and for automatically shutting off the wiper unitsubsequent to the cessation of washer operation. The electrical controlsystem comprises a power source, an electric motor means, anelectrically operated washer unit and a first control circuit meansincluding a manual switch for effecting either low or high speedcontinuous operation of the wipers and a second control circuit meansincluding a manually operated washer switch for controlling operation ofthe washer unit and for initiating conjoint operation of the wiper unitwith the wiper unit shutting off automatically subsequent to thecessation of washer operation.

3 Claims, 1 Drawing Figure PATENTEDSEP 12 I972 3.6 91 442 INVENTOR.

kamrdJS/zeldmke 144% A {TO H Y CONTROL CIRCUIT FOR AUTOMATICALLYSHUTTING OFF THE WlNDSI-IIELD WIPERS SUBSEQUENT TO WASHER OPERATION Thepresent invention relates to a control system for controlling operationof the windshield wiper unit, and in particular to an electrical controlsystem for controlling conjoint operation of the windshield wiper andwasher units and in which the wiper unit is shut off at a predeterminedtime subsequent to the cessation of washer operation.

Heretofore, electrical control systems for controlling operation of awindshield wiper unit and a washer unit for an automotive vehicle havebeen provided. These known systems have included a manually operableswitch means for effecting either low or high speed continuous operationof a wiper motor for oscillating a pair of windshield wipers and asecond manual control switch which is momentarily depressible to effectenergization of an electrically operated washer unit.. These knownsystems have also included a manually depressable switch for energizingthe washer unit and energizing the wiper unit and with the wiper unitshutting off automatically subsequent to the cessation of washeroperation. ln these latter systems the wiper motor is kept energizedsubsequent to the cessation of washer opera tion by a time delay meansin the form of a mechanical timer, a pneumatic timer or an electricaltimer. Electrical timers have included bimetal switches and R-C timerswherein a discharging capacitor governs the length of time the wiperunit remains energized.

The present invention provides an electrical control system forcontrolling operation of the wiper and washer units of an automotivevehicle and which includes l a first conventional control circuit meansincluding a first manual switch means effecting either high or low speedcontinuous operation of the windshield wipers and a second manualcontrol switch for controlling operation of the washer unit, and (2) anovel second control circuit means which is responsive to momentarydepression of the washer switch to effect simultaneous or conjointoperation of the windshield wiper and washer units and with the wiperunit shutting off at a predetermined time subsequent to the cessation ofwasher operation.

Accordingly, an important object of the present invention is to providea new and improved electrical control system for effecting conjointoperation of the windshield wiper and washer unit of an automotivevehicle and in which the wiper unit shuts off automatically subsequentto the cessation of washer operation and which includes a controlcircuit means having transistor means for controlling energization of anelectric motor, a controlled switch for controlling current flow to thetransistor means, an R-C time delay means including a capacitoroperatively connected with the transistor means and the controlledswitch and a momentarily actuatable washer switch operatively connectedwith the capacitor and the washer unit, and in which the control circuitmeans functions to charge the capacitor when the automotive vehicle isoperating and apply positive voltage to the base of the transistor meansand the controlled switch to render them nonconductive, to immediatelydischarge the capacitor when the washer switch is momentarily closed andremove the positive voltage from the base of the transistor and thecontrolled switch to turn them on and thereby effect conjointenergization of the wiper unit and washer unit and to maintain the wiperunit energized until the transistor means is turned off upon thecapacitor being recharged.

The present invention further resides in various novel constructions andarrangement of parts, and further objects, novel characteristics andadvantages of the present invention will be apparent to those skilled inthe art to which it relates and from the following detailed descriptionof the illustrated embodiment thereof made with reference to theaccompanying drawing forming a part of this specification and in which:

The drawing schematically shows the preferred embodiment of theelectrical control system for controlling operation of a wiper unit andwasher unit for an automotive vehicle of the present invention.

As representing a preferred embodiment of the present invention, thedrawing shows an electrical control system for controlling operation ofan electric motor means 12 of a windshield wiper unit and a relay 14 ofa windshield washer unit 16 for an automotive vehicle (not shown). Thecontrol system broadly comprises a first control circuit means,designated generally by the reference numeral 10, which is selectivelyoperable to effect continuous operation of a DC unidirectional wipermotor 12 at either low or high speed and selectively operable to effectenergization of the relay 14 of the washer unit 16. The electricalcontrol systems further include a second control circuit means,designated generally by the reference numeral 20, which is connected inparallel with the first control circuit means and which is selectivelyoperable to effect conjoint operation of the washer unit 16 and thewiper unit and to automatically shut off the wiper unit at apredetermined time period subsequent to the cessation of washeroperation.

The first control circuit means 10 includes a battery 24, a vehicleignition switch 26, the electric motor means 12, a resistor 28, amanually manipulatable wiper switch 30, the washer unit relay l4, and amanually manipulatable washer unit switch 32. The battery 24 has oneterminal connected via wire or conductor 34 to ground G: and its otherterminal connected via wire 36 to the ignition switch 26.

The electric motor means 12 comprises an armature 40, series fieldwinding 42 connected in series with the armature 40, a shunt fieldwinding 44, the resistor 28 and a park switch 46 and its associatedrelay 47. The park switch 46 includes a stationary contact 46a and amovable contact 46b carried by a leaf spring 460. The leaf spring 460 isinherently self-biased toward a closed position in which the contacts46b and 46a engage each other, but is normally held open in oppositionto its biasing force by a cam 48 eccentrically secured to the armature40. The cam 48 is in the position shown in the drawing in which it holdsthe park switch 46 in its open position when the wiper motor 12 isde-energized.

The wiper unit could be of any suitable or conventional construction,but is preferably of the type shown and described in US. Pat. No.3,253,206. Likewise, the washer unit 16 could be of any suitable orconventional construction, but is preferably a programmed washer unitwhich operates for a predetermined number of cycles of operation of thewiper unit upon its associated relay coil 14 being momentarilyenergized. The washer unit 16 is preferably like that shown in US. Pat.No. 3,503,090.

The manual control switch 30 could be of any suitable or conventionalconstruction, but is preferably of the type which includes a wiperswitch actuator which is movable between ofi, low and high speedpositions. The washer switch 32 includes a push button washer switchactuator 49 which can be depressed to initiate washer operation. Thewasher switch actuator 49 is normally spring biased toward an openposition, as shown in the drawing, but is momentarily depressible inopposition to the biasing force of the spring to bridge a pair ofcontacts 50 and 51.

As schematically shown in the drawing, the manually manipulatable wiperswitch 30 includes a pair of stationary metal contacts 52 and 54 and amovable bridging member 56. The bridging member 56 is connected to asuitable ground G, via a wire 57. The movable contact 56 is movable froman off position to either a low or high speed position in which itrespectively bridges the stationary contacts 52 and 54 and bridges onlythe contact 54.

Operation of the control circuit means will be described with referenceto the drawing. When the operator of the vehicle desires continuous lowspeed operation of the wiper motor 12, he will actuate the wiper switch30 to move the bridging member 56 from its off position to its low speedposition. When the bridging member 56 is moved to its low speed positiona circuit A for energizing the relay coil 47 for moving the park switch46 to its closed position is energized. Circuit A is from battery 24,wire 36, ignition switch 26, wire 38, circuit breaker 37, wire 60, relaycoil 47, wire 61, stationary contact 54, bridging member 56, wire 57 toground G When the relay coil 47 is energized the leaf spring member 46of the park switch is caused to be moved in opposition to the cam 48 toits closed position in which the contacts 46a and 46b engage each other.The engagement of these contacts will complete circuits B and C forenergizing the wiper motor 12. Circuit B is from battery 24, wire 36,ignition switch 26, wire 38, circuit breaker 37, wire 60, now closedcontacts 460 and 46b of park switch 46, wire 62, series field windings42, wire 64, armature 40, wire 65, motor circuit breaker 66, wire 67, toground G The circuit C is from wire 64, shunt field windings 44, wire68, stationary contact 52, bridging member 56, wire 57, to ground 0,.The electric motor 12 will operate at low speed to continuously operatethe wipers at low speed as long as the bridging member remains in itslow speed position.

When the operator desires high speed operation of the wiper motor 12, hewill actuate the wiper switch to move the bridging member 56 to its highspeed position. Movement of the bridging member 56 to its high speedposition completes the hereinbefore described circuit A for energizingthe park switch relay 47. When the park switch relay 47 is energized thepark switch 46 is moved to its closed position, which in turn completesthe hereinbefore described circuit B for energizing the series fieldwinding 42 and armature 40 of the wiper motor 12. The hereinbeforedescribed circuit C for energizing the shunt field windings 44, however,is not energized when the bridging member 56 is in its high speedposition, since the latter is no longer engaged with the stationarycontact 52 and hence the ground path to G is broken. Movement of thebridging member 56 to the high speed position, however, completes acircuit D for energizing the shunt field windings 44 through theresistor 28, which is connected to the wire 68 and connected to a groundG via a wire 70. When the shunt field windings 44 are energized throughtheir resistor 28, high speed operation of the wiper motor is effected,and in a manner well known to those skilled in the art.

When the bridging contact 56 of the wiper switch 30 is in either its lowor high speed position, the washer unit 16 can be energized in responseto momentary depression of the switch member 49 of the washer switch 32to its closed position to bridge the contacts 50 and 51. This completesthe circuit E for energizing the relay coil 14 for initiating operationof the washer unit 16. The circuit E is from battery 24, wire 36, igni'tion switch 26, wire 38, circuit breaker 37, wire 60, relay coil 14,wire 71, switch contact 50, switch member 49, switch contact 51, wire 72to ground G As alluded to hereinbefore, the washer unit 16 is preferablya programmed washer unit which upon momentary energization of the relaycoil 14 operates for a predetermined number of wiper strokes and thenautomatically shuts off.

In accordance with the provisions of the present invention, theelectrical control system also includes a second control circuit means20 connected in parallel with the first control circuit means 10 andwhich is operable in response to momentary depression of the washerswitch 32 to effect conjoint operation of the washer unit 16 and thewiper unit and with the wiper unit shutting off after a predeterminednumber of cycles of operation subsequent to the cessation of washeroperation.

The control circuit means 20 includes a first NPN transistor having acollector 81 connected via wire 61 to the park switch relay coil 47, anemitter 82 connected via wire 83 to ground G and a base 84. The base 84of the NPN transistor 80 is connected via a wire 85 to a collector 86 ofa second PNP transistor 87. The PNP transistor 87 also has an emitter 88and a base 89.

The control circuit means 20 further includes a suitable or conventionalcontrolled or control gate switch 90 having an anode 91, a cathode 92and a gate 93. The anode 91 is connected to wire or conductor 61, andthe cathode 92 is connected via a wire 95 to the emitter 88 of thetransistor 87. The control switch 90 functions to control the currentflow through the emitter-collector circuit of the transistor 87 and isof the type which is biased on when the gate voltage is negativerelative to the voltage of the anode and remains biased on, even whenthe gate voltage subsequently becomes positive, until the transistor 87is turned off. The controlled switch 90 could be an SCR, but ispreferably a PUT transistor.

The control circuit means 20 further includes a first R-C electricaltime delay means 100. The R-C electrical time delay means comprises acapacitor 102 whose negative side is connected via wire 103 to a groundG and whose positive side is connected via a wire 105 to one end of aresistor 106 and one end of a resistor 107. The other end of theresistor 106 is connected via wire 108 to the base of transistor 87 andthe other end of the resistor 107 is connected via a wire or conductor110 to the wire 71. A diode 112 is connected in parallel with theresistor 107 and to the wires 105 and 110. The control circuit meansadditionally includes a second RC time delay means comprising acapacitor 120 having one side connected to the wire 61 and its otherside connected via wire 121 to the gate 93 of the controlled switch 90and a resistor 122 having one end connected to the wire 121 and itsother end connected to the wire 110. In the preferred embodiment, theresistor 106 has a resistance of 4.7 k ohms, the resistor 107 has aresistance of 470 k ohms and the resistor 122 has a resistance of 100 kohms. The capacitor 102 is a 20 microfarad capacitor and the capacitor120 is a 0.22 microfarad capacitor.

When the ignition switch 26 is turned on positive voltage from thebattery 24 is applied to the anode 91 of the control switch via wire 60,park switch relay 47 and wire 61. Positive voltage is also applied tothe gate 93 of the controlled switch 90 and to the base 89 of thetransistor 87 via the washer relay 14, wire 110 and through theresistors R';, and R and R respectively. Also with the ignition switch26 on, the capacitor 102 is fully charged.

When the operator of the vehicle desires to initiate conjoint washer andwiper operation and with the wipers shutting off automaticallysubsequently to the cessation of washer operation, he will merelydepress the washer button switch 32. Depression of the washer buttonswitch completes the hereinbefore described circuit E for energizing therelay coil 14 of the washer unit 16. The depression of the washer button32 also causes the capacitor 102 to be immediately discharged throughwire 105, diode 112, wire 110, wire 71, and through the washer button 49to ground G When the capacitor 102 is discharged the positive voltage atthe base of the transistor 87 and the gate of the control switch 90 isremoved. This biases the PNP transistor 87 on and biases the controlswitch 90 on. When this occurs current flows from the anode 91 of thecontrol switch to the cathode 92 thereof and thence through theemitter-collector circuit of the transistor 87 to apply positive voltageto the base of the transistor 80. When this occurs the transistor 80 isturned on to complete a circuit for the park switch relay 47 to effectenergization of the wiper motor 12. This circuit is from battery 24,wire 37, ignition switch 26, wire 38, circuit breaker 37, wire 60, parkswitch relay 47, wire 61, collector 81, emitter 82 of transistor 80,wire 83 to ground G When the park switch relay 47 is energized the parkswitch 46 is moved to its closed position to effect energization of theseries field windings 42 and armature 40 of the wiper motor and theshunt field windings 44 of the wiper motor, and in the same manner asthat hereinabove described with reference to continuous low speedoperation.

When the washer button switch 32 is released, the ground path to theground G is broken and the capacitor 102 begins to charge. The capacitor102 begins to charge both as a result of leakage current from theemitter to base circuit of the transistor 87 and through the relay coil14 and resistor 107. The transistor 87 remains biased on until thecapacitor 102 is fully charged, and with the length of time required tocharge the capacitor 102 being primarily governed by the resistor 107.It should be noted that even though positive voltage is applied to thegate 93 of the controlled switch 90 when the washer button 49 isreleased, the controlled switch 90 remains energized, since once it isturned on it will remain energized until the transistor 87 is biasedoff.

When the capacitor 102 is fully charged, positive battery voltage isagain applied to the base of the transistor 87, which turns off thetransistor 87. This in turn interrupts the emitter to collector circuitof the transistor 87, which in turn biases off the N PN transistor 80.When the transistor is biased off, the wiper motor 12 is de-energized.Also turning off the transistor 87 causes the control'switch 90 to beturned off, since the transistor 87 is no longer conducting currentthrough its emitter to collector circuit. It the windshield wipersshould not be in their inboard or park position when the wiper motor 12is de-energized, the motor 12 will remain energized until the wipersreach their park position due to the provision of the cam 48 and parkswitch 46, which is biased to a closed position. When the wipers reachtheir park position, the cam 48 opens the park switch 46 to effectde-energization of the wiper motor 12.

The time delay means is preferably such that the wiper unit would remainenergized for one or two cycles of operation subsequent to the cessationof washer unit operation. The primary function of the controlled switch90 is to prevent energization of the wiper unit upon turning on theignition switch 26 of the vehicle. This is because when the vehicle issitting idle with the ignition switch 26 off the charge on the capacitor102 tends to leak off. Thus, when the ignition switch 26 is turned onthe voltage at the base of the transistor 87 would be momentarilynegative with respect to the voltage at the emitter 88 thereof, due tothe resistors 106 and 107. To prevent the wiper unit from being turnedon each time the ignition switch 26 is turned on, the control switch 90is employed which serves to block any positive voltage being applied tothe emitter 88 of the transistor 87. Therefore, the only time thecontrol circuit means 20 can be energized is when the capacitor 102 ispurposely discharged subsequent to the ignition switch 26 being turned.The capacitor serves as the filter capacitor to filter out voltagespikes, noise, etc.

An important advantage of the control circuit means 20 is that thelength of time the wiper unit remains energized is governed by thelength of time required to charge the capacitor 102. In previous orknown R-C time delay circuits the length of time the wiper unit wasenergized depended upon the length of time the capacitor discharged,which in turn required a very carefully controlled discharge rate tooperate properly, i.e., to insure the wiper unit remained energized onlyfor a predetermined time period. Since the time to control the chargingof a capacitor can be more readily controlled, the instant controlcircuit means provides for a very accurate control.

Although the illustrated embodiment hereof has been described in greatdetail, it should be apparent that certain modifications, changes, andadaptations may be made in the illustrated embodiment, and that it isintended to cover all such modifications, changes and adaptations whichcome within the spirit of the present invention.

What is claimed is:

1. An electrical control system for controlling operation of awindshield wiper unit for a predetermined length of time and thenautomatically de-energize the same comprising:

a DC power source:

an ignition switch;

an electric motor means operatively connected with said power sourcethrough said ignition switch;

a transistor means operatively connected with said motor means andeffecting energization of the latter when biased on;

a controlled switch for controlling current flow to the transistormeans, said controlled switch having an anode connected with said powera source, a cathode connected with said transistor means and a gate;

an R-C time delay means including a capacitor operatively connected withsaid power source, the gate of said controlled switch and saidtransistor means at its base,

said capacitor being charged when said ignition switch is on and saidgate of said controlled switch and said base of said transistor meansbeing applied with positive voltage when said ignition switch is on;

a manually manipulatable momentary switch connected in series with saidcapacitor and being operable when moved momentarily to a closed positionto directly connect the capacitor to ground and thereby remove thepositive voltage from the base of the transistor means and the gate ofthe controlled switch whereby the control switch is rendered conductiveand the transistor is biased on to effect energization of the electricmotor means, said controlled switch being biased on until said capacitoris recharged whereupon said transistor means is biased off and saidelectric motor is de-energized.

2. An electrical control system for controlling operation of awindshield wiper unit and a washer unit and for automatically shuttingoff the wiper unit subsequent to the cessation of washer unit operationcomprising:

a DC power source;

an ignition switch;

an electric motor means operatively connected with said power sourcethrough said ignition switch;

a transistor means operatively connected with said motor means andeffecting energization of the latter when biased on;

a controlled switch for controlling current flow to the transistormeans, said controlled switch having an anode connected with said powersource, a cathode connected with said transistor means and a gate;

an R-C time delay means including a capacitor operatively connected withsaid power source, the gate of said controlled switch and saidtransistor means at its base,

said capacitor being charged when said ignition switch is on and saidgate of said controlled switch and said base of said transistor meansbeing applied with positive voltage when said ignition switch is on;

a washer unit relay;

a manually manipulatable momentary switch connected in series with saidwasher unit relay and with said capacitor and being operable when movedmomentarily to a closed position to effect energization of the washerunit relay and directly connect the capacitor to ground and therebyremove the positive voltage from the base of the transistor means andthe gate of the controlled switch whereby the controlled switch isrendered conductive and the transistor is biased on to effectenergization of the electric motor means, said controlled switch beingbiased on until said capacitor is recharged whereupon said transistormeans is biased off and said electric motor is de-energized.

3. An electrical control system for initiating conjoint operation of awindshield wiper unit and a windshield washer unit and for automaticallyshutting off the wiper unit subsequent to the cessation of washer unitoperation comprising:

a DC power source; an ignition switch connected with said power source;

an electric motor means;

an NPN transistor for effecting energization of said motor means whenbiased on;

a PNP transistor;

a controlled switch for controlling current flow to the transistormeans, said controlled switch having an anode connected with said powersource, a cathode connected with the emitter of said PNP transistor anda gate, said PNP transistor having its collector connected to the baseof said NPN transistor, said NPN transistor having its collectorconnected with said electric motor means and its emitter connected witha ground, said gate of said controlled switch being connected via aresistor in series with said power source; an R-C time delay meansincluding a capacitor and second and third resistors, said capacitorbeing connected via said second resistor with said power source and viasaid third resistor to the base of said PNP transistor;

a momentarily actuatable manual control switch, a washer unit relay,said controlled switch being connected in series with said washer unitrelay and being connected in series with said capacitor, said capacitorbeing charged when said ignition switch is on and positive voltage fromsaid power source being supplied to the base of the PNP transistor andto the gate of the controlled switch to render the PNP transistor andthe controlled switch nonconductive, said manual switch when momentarilyactuated providing a ground path to immediately discharge the capacitorand to energize the relay of the washer unit, said capacitor whendischarged functioning to turn on the PNP transistor and to render thecontrolled switch conductive to current whereby said NPN transistor isbiased on and said electric motor means is energized, said capacitorrecharging upon release of said manual controlled switch at a'rategoverned by the second and third resistors and when charged apredetermined amount effecting a positive bias on the PNP transistor toturn the first transistor off, which in turn turns the controlled switchoff and de-energizes said electric motor means.

P0-1-Q50- muss STATES ?ATENT swim:

Ww) CERTIFECATE 0F mR-REQ'HON' j Patent No. 3.6g] 45g Dated sgggem'berl2 1 972 Inventor(s) Leonard J sheldrake It is certified that etro rappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

T e "'i column 2, line 47 "G" should read --.s Column 3, line 21, "G"should read --G Column 6, line 20 "It" should read --If--.

Signed and sealed this 29th day of May 1973.

Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer 1 Commissionerof Patents W050 m me sm'ree PATENT ewiee'i (5/69) h l h .v Y .7

eime'm @i eeemew Patent No; 3 691,442 Dated September 12 I 1 972Inventor(s) Leonard J. Sheldrake It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

i" I a C01 2, line e7 "G" eheulfi read --G Column 3, line 21., "G"should read --G 6, line 20 "It" shoulfl reafi -If-,

Signed and sealed this 29th day of May 1973.

( A Attes't:

EDWARD M.FLET'CHER,JR. ROBERT GOTT SCHALK Attesting Officer Commissionerof Patents

1. An electrical control system for controlling operation of awindshield wiper unit for a predetermined length of time and thenautomatically de-energize the same comprising: a DC power source: anignition switch; an electric motor means operatively connected with saidpower source through said ignition switch; a transistor meansoperatively connected with said motor means and effecting energizationof the latter when biased on; a controlled switch for controllingcurrent flow to the transistor means, said controlled switch having ananode connected with said power source, a cathode connected with saidtransistor means and a gate; an R-C time delay means including acapacitor operatively connected with said power source, the gate of saidcontrolled switch and said transistor means at its base, said capacitorbeing charged when said ignition switch is on and said gate of saidcontrolled switch and said base of said transistor means being appliedwith positive voltage when said ignition switch is on; a manuallymanipulatable momentary switch connected in series with said capacitorand being operable when moved momentarily to a closed position todirectly connect the capacitor to ground and thereby remove the positivevoltage from the base of the transistor means and the gate of thecontrolled switch whereby the control switch is rendered conductive andthe transistor is biased on to effect energization of the electric motormeans, said controlled switch being biased on until said capacitor isrecharged whereupon said transistor means is biased off and saidelectric motor is de-energized.
 2. An electrical control system forcontrolling operation of a windshield wiper unit and a washer unit andfor automatically shutting off the wiper unit subsequent to thecessation of washer unit operation comprising: a DC power source; anignition switch; an electric motoR means operatively connected with saidpower source through said ignition switch; a transistor meansoperatively connected with said motor means and effecting energizationof the latter when biased on; a controlled switch for controllingcurrent flow to the transistor means, said controlled switch having ananode connected with said power source, a cathode connected with saidtransistor means and a gate; an R-C time delay means including acapacitor operatively connected with said power source, the gate of saidcontrolled switch and said transistor means at its base, said capacitorbeing charged when said ignition switch is on and said gate of saidcontrolled switch and said base of said transistor means being appliedwith positive voltage when said ignition switch is on; a washer unitrelay; a manually manipulatable momentary switch connected in serieswith said washer unit relay and with said capacitor and being operablewhen moved momentarily to a closed position to effect energization ofthe washer unit relay and directly connect the capacitor to ground andthereby remove the positive voltage from the base of the transistormeans and the gate of the controlled switch whereby the controlledswitch is rendered conductive and the transistor is biased on to effectenergization of the electric motor means, said controlled switch beingbiased on until said capacitor is recharged whereupon said transistormeans is biased off and said electric motor is de-energized.
 3. Anelectrical control system for initiating conjoint operation of awindshield wiper unit and a windshield washer unit and for automaticallyshutting off the wiper unit subsequent to the cessation of washer unitoperation comprising: a DC power source; an ignition switch connectedwith said power source; an electric motor means; an NPN transistor foreffecting energization of said motor means when biased on; a PNPtransistor; a controlled switch for controlling current flow to thetransistor means, said controlled switch having an anode connected withsaid power source, a cathode connected with the emitter of said PNPtransistor and a gate, said PNP transistor having its collectorconnected to the base of said NPN transistor, said NPN transistor havingits collector connected with said electric motor means and its emitterconnected with a ground, said gate of said controlled switch beingconnected via a resistor in series with said power source; an R-C timedelay means including a capacitor and second and third resistors, saidcapacitor being connected via said second resistor with said powersource and via said third resistor to the base of said PNP transistor; amomentarily actuatable manual control switch, a washer unit relay, saidcontrolled switch being connected in series with said washer unit relayand being connected in series with said capacitor, said capacitor beingcharged when said ignition switch is on and positive voltage from saidpower source being supplied to the base of the PNP transistor and to thegate of the controlled switch to render the PNP transistor and thecontrolled switch non-conductive, said manual switch when momentarilyactuated providing a ground path to immediately discharge the capacitorand to energize the relay of the washer unit, said capacitor whendischarged functioning to turn on the PNP transistor and to render thecontrolled switch conductive to current whereby said NPN transistor isbiased on and said electric motor means is energized, said capacitorrecharging upon release of said manual controlled switch at a rategoverned by the second and third resistors and when charged apredetermined amount effecting a positive bias on the PNP transistor toturn the first transistor off, which in turn turns the controlled switchoff and de-energizes said electric motor means.